Sony are pretty aggressive when it comes to blocking cross platform online gameplay. Unless Sony grant this for Minecraft, the bedrock condition will never come to the PS4. Sony have allowed rocket league and Fortnite cross play so there is a chance this can be done if there is enough demand from the community to make it happen.
I'm finding this to be really annoying. One thing that has always been a bit of a pain is the fact that every system seems to have a different version of the game. It makes it a nightmare when you are trying to find some good seeds. Unifying the systems using the bedrock edition makes so much sense! I know this is all down to Sony being uncooperative when it comes to cross platform play on the PS4 but the devs seem into it and now that Fortnite and Rocket League have it, why not Minecraft?